Prejudicial Joinder of Multiple Offenses: Relative Effects of Cognitive Processing and Criminal Schema

The relative contributions of cognitive processing of evidence and invocation of a criminal schema to the effects of joinder of offenses was investigated. One hundred forty simulated jurors either judged no evidence or judged evidence from one or two charges with the knowledge that the defendant had been charged with either one, two, three, or four offenses. The results showed that guilt evaluations, defendant character ratings, and measures of memory were influenced more by the number of charges judged than by the number of charges filed. Results from two path analyses suggest that the joinder effect is mediated by both cognitive factors and judgments about the defendant's character. Joinder appears to affect the cognitions generated about the cases, which in turn affect perceptions of the defendant and ultimately guilt assessment.